grant run-time environments their own modules with their own description

deployment/data-model.nix

@@ -4,12 +4,19 @@
   ...
 }:
 let
-  inherit (lib) attrNames mkOption genAttrs;
+  inherit (lib)
+    attrNames
+    mapAttrs
+    mkOption
+    genAttrs
+    ;
   inherit (lib.types)
     attrsOf
     attrTag
     deferredModule
+    mergeTypes
     submoduleWith
+    submodule
     ;
   runtime-configuration = mkOption {
     description = "The NixOS module of a run-time environment";
@@ -21,26 +28,28 @@ let
   runtime-environment = attrTag (
     mapAttrs
       (
-        name: options:
+        name:
-        mkOption {
+        option@{ type, ... }:
-          type = submoduleWith {
+        mkOption (
-            modules = [
+          option
-              {
+          // {
-                options = options // {
+            type = mergeTypes type (submodule {
-                  module = mkOption {
+              options.module = mkOption {
-                    description = "The NixOS module of the run-time environment";
+                description = "The NixOS module of the run-time environment";
-                    type = deferredModule;
+                type = deferredModule;
-                    default = config.runtime-configurations.${name};
+                default = config.runtime-configurations.${name};
-                    readOnly = true;
+                readOnly = true;
-                  };
+              };
-                };
+            });
-              }
+          }
-            ];
+        )
-          };
-        }
       )
       {
-        nixos = { };
+        nixos = {
+          description = "A NixOS instance to deploy to.";
+          type = submodule {
+          };
+        };
       }
   );
   application = submoduleWith {